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Density and confinement effects of glass forming m-toluidine in nanoporous Vycor investigated by depolarized dynamic light scattering

Blochowicz, T. and Gouirand, E. and Schramm, S. and Stühn, B. (2013):
Density and confinement effects of glass forming m-toluidine in nanoporous Vycor investigated by depolarized dynamic light scattering.
In: JOURNAL OF CHEMICAL PHYSICS, p. 114501, 138, (11), [Online-Edition: http://dx.doi.org/10.1063/1.4793762],
[Article]

Abstract

We investigate the reorientational dynamics of supercooled m-toluidine contained in a matrix of nanoporous Vycor with depolarized dynamic light scattering. Under equilibrium conditions a clear sample is obtained and the dynamics of m-toluidine molecules from inside the nanopores can be accessed via light scattering. However, when supercooling the imbibed liquid at conventional cooling rates, strong non-equilibrium effects occur due to the mismatch of expansion coefficients and the sample gets turbid several tens of Kelvin above the bulk glass transition. Only at cooling rates as low as 0.02 K/min this can be avoided and the dynamics of m-toluidine in confinement can be followed even below the bulk glass transition temperature. In confinement a pronounced acceleration of the reorientational dynamics is observed and the characteristic correlation times follow an Arrhenius law close to T-g. However it seems likely that part of the observed differences to bulk behavior is due to density effects, which are reduced but cannot be fully avoided at low cooling rates. (C) 2013 American Institute of Physics. http://dx.doi.org/10.1063/1.4793762]

Item Type: Article
Erschienen: 2013
Creators: Blochowicz, T. and Gouirand, E. and Schramm, S. and Stühn, B.
Title: Density and confinement effects of glass forming m-toluidine in nanoporous Vycor investigated by depolarized dynamic light scattering
Language: English
Abstract:

We investigate the reorientational dynamics of supercooled m-toluidine contained in a matrix of nanoporous Vycor with depolarized dynamic light scattering. Under equilibrium conditions a clear sample is obtained and the dynamics of m-toluidine molecules from inside the nanopores can be accessed via light scattering. However, when supercooling the imbibed liquid at conventional cooling rates, strong non-equilibrium effects occur due to the mismatch of expansion coefficients and the sample gets turbid several tens of Kelvin above the bulk glass transition. Only at cooling rates as low as 0.02 K/min this can be avoided and the dynamics of m-toluidine in confinement can be followed even below the bulk glass transition temperature. In confinement a pronounced acceleration of the reorientational dynamics is observed and the characteristic correlation times follow an Arrhenius law close to T-g. However it seems likely that part of the observed differences to bulk behavior is due to density effects, which are reduced but cannot be fully avoided at low cooling rates. (C) 2013 American Institute of Physics. http://dx.doi.org/10.1063/1.4793762]

Journal or Publication Title: JOURNAL OF CHEMICAL PHYSICS
Volume: 138
Number: 11
Divisions: 05 Department of Physics > Institute for condensed matter physics > Experimental Condensed Matter Physics
05 Department of Physics > Institute for condensed matter physics
05 Department of Physics
Date Deposited: 06 May 2013 06:47
Official URL: http://dx.doi.org/10.1063/1.4793762
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